Wall = function(pos, start, end, isVertical) {
	this.pos = pos;
	this.start = start;
	this.end = end;

	var hwt = WALL_THICKNESS / 2;
	if (isVertical) {
		this.poly = [[pos - hwt, start - hwt], [pos - hwt, end + hwt], [pos + hwt, end + hwt], [pos + hwt, start - hwt]];
	} else {
		this.poly = [[start - hwt, pos - hwt], [end + hwt, pos - hwt], [end + hwt, pos + hwt], [start - hwt, pos + hwt]];
	}
		
	this.get_collision_poly = function() {
		return this.poly;
	}
	
    this.draw = function(c, gs) {
		gs.polygon(this.poly);
    }
}